Is it true that the more “scattered” an array of numbers is, the longer it will take to sort it (say, with a bubble)?

Question

Algorithms

Let's say if I sort 2 separate arrays, then merge them into one by adding elements of one between the elements of the other (like braiding a pigtail), and then sort the resulting array again, then this last sort will take less time than if I initially had 1 array?
If you don't feel like answering the second question, answer the first.

Answer 1

For bubble sort
For the above approach (separately sort the parts then merge), merge-sort is used.

Answer 2

1. In general, no.
2. Maybe yes, maybe not. Strongly depends on the used algorithm and elements of arrays.

Answer 3

Very similar to merge sort and heapsort. In order not to invent these sorts (which, of course, are faster than bubble sort), it is better to find their description and implement each separately.